What is a cross-platform way to get the current directory?

Question

I need a cross-platform way to get the current working directory (yes, getcwd does what I want). I thought this might do the trick:

#ifdef _WIN32     #include <direct.h>     #define getcwd _getcwd // stupid MSFT "deprecation" warning #elif     #include <unistd.h> #endif #include <string> #include <iostream> using namespace std;  int main() {     string s_cwd(getcwd(NULL,0));     cout << "CWD is: " << s_cwd << endl; } 

I got this reading:

• _getcwd at MSDN
• getcwd at Kernel.org
• getcwd at Apple.com

There should be no memory leaks, and it should work on a Mac as well, correct?

UPDATE: I fear something is still wrong here (I'm trying to avoid creating a char array with a determined length, as there's no proper way to get a decent length for getcwd):

char* a_cwd = getcwd(NULL,0); string s_cwd(a_cwd); free(a_cwd); // or delete a_cwd?  

Answer 1

If it is no problem for you to include, use boost filesystem for convenient cross-platform filesystem operations.

boost::filesystem::path full_path( boost::filesystem::current_path() ); 

Here is an example.

EDIT: as pointed out by Roi Danton in the comments, filesystem became part of the ISO C++ in C++17, so boost is not needed anymore:

std::filesystem::current_path(); 

Answer 2

You cannot call getcwd with a NULL buffer. As per the Opengroup:

If buf is a null pointer, the behavior of getcwd() is unspecified.

Also, getcwd can return NULL which can break a string constructor.

You'll need to change that to something like:

char buffer[SIZE]; char *answer = getcwd(buffer, sizeof(buffer)); string s_cwd; if (answer) {     s_cwd = answer; }